Researchers had trouble identifying the connection between Chemotherapy and loss of brain function in the past. They were using MRIs to analyze the change in the brain's appearance. Only small changes in brain volume were detected. However, this time around, scientists used PET and CT scans to look at chemo's affect on brain function and metabolism.

After looking at images from the brains of 128 people who had been through chemo treatment for breast cancer, doctors found a very clear cut connection. Post-chemo, there are specific areas of the brain—the ones devoted to planning and prioritizing—that use less energy. While this might be an unfortunate and unavoidable side-effect, now doctors are aware that it's real. And that means there's room for early intervention, and at the very least to prepare patients and their families for what might be ahead. [Yahoo News, h/t @Xeni]